1. Field of the Invention
The present invention relates to a material supplying system and material supplying method used in a broadcast station or the like, in particular, to a supplying system for effectively using a material whose use frequency is high.
2. Description of the Related Art
In a broadcast station or the like, commercials (hereinafter referred to as CMs) and programs are broadcast by supplying visual/audio materials (hereinafter referred to as materials) recorded on video tapes or stored in disc units. A supplying system that supplies such materials has for example a material storage unit that stores all materials to be supplied and a supply buffer unit that temporarily stores only materials that will be supplied in for example several hours.
In such a conventional supplying system, materials are copied from the material storage unit to the supply buffer unit before supply date/time corresponding to a list that represents supply materials and supply time thereof (hereinafter, the list is referred to as a play list). At the supply time, the copied materials are output from the supply buffer unit. The supplied materials are deleted from the supply buffer unit after the materials have been supplied or when new materials are copied from the material storage unit. Alternatively, the materials are deleted when the material buffer unit does not have an area for temporarily storing new materials to be supplied.
However, in the conventional supplying system, since materials that were supplied are deleted, if the materials are CM materials that are frequently supplied and repeatedly used, the materials are copied from the material storage unit to the supply buffer unit whenever the materials are supplied. Thus, it takes time to copy the materials, thereby adversely affecting the copying operation for other materials.
Particularly, in a supplying system that supplies a plurality of materials to respective channels, this problem becomes exacerbated. Such a supplying system having a plurality of channels is composed of one material storage unit and a plurality of supply buffer units corresponding to the channels. Thus, in the supplying system having the plurality of channels, copying operation time for each supply buffer unit is restricted. Consequently, the number of times of the copying operation for each supply buffer unit should be suppressed. However, in such a conventional supplying system, it takes time for the copying operation for materials that are repeatedly supplied, thereby remarkably disturbing the copying operation for other materials.
In addition, a check operation for determining whether or not a material was normally copied from the material storage unit to a relevant supply buffer unit was performed by reproducing a copied material from the supply buffer unit. In the conventional supplying system, even materials that are repeatedly used are deleted from relevant supply buffer units once they were supplied. Thus, the check operation should be performed whenever each material that is repeatedly used is copied. Consequently, a substantially wasteful operation is required.